Reversing apparatus for furnaces



9, 1939. G. A. MERKT 2,157,771

REVERSING APPARATUS FOR FURNACES Filed Feb. 8, 1937 4 Sheets-Sheet l INVENTOR GusTA v A. MERKT Saw aw ATTORNEY G. A. MERKT REVERSING APPARATUS FOR FURNACES Filed Feb. 8, 1937 4 Sheets-Sheet 2 /NVENTOR Gus TA v A. MERKT AT7'ORNE May 9, 1939. ca. A. MERKT REVERSING APPARATUS FOR FURNACES Filed Feb. 8, 1957 4 Sheets-Sheet 3 J l l INVENTOR 1%Y K E m m AA w Y m5 G y 9, 1939. G. A. MERKT 2,157,771

REVERSING APPARATUS FOR FURNACES Filed Feb. 8, 1937 4 Sheets-Sheet 4 P KO INVENTOR GUSTAV A .MERKT ATToRNE Y FIG-.6

Patented May 9, 1939 UNITED STATES PATENT OFFICE Morgan Construction Company,

Worcester,

Mass, a corporation of Massachusetts Application February 8, 1937, Serial No. 124,781

11 Claims.

This invention relates to reversing apparatus for furnaces, and more particularly to apparatus for use with furnaces of the type having a supply of air which is used alternately to support the combustion of fuel and to cause ejection of the gaseous products of combustion. Such furnaces are usually provided with a pair of regenerators, one of which is being heated by the waste gases while the other is giving up heat to the combustion air.

t is found in practice that the quantity of air required for combustion purposes is usually different from the quantity required to effect ejection of the gases. In some cases the quantity of combustion air will exceed the quantity of ejection air, whereas in other cases more air will be required for ejection than for combustion. Furthermore, it is often impossible to ascertain, in advance of actual installation and trial, which of these air requirements will be the higher in a particular case. The problem is further complicated by the fact that in some cases it is necessary to adjust the air quantities during the operation of the furnace to obtain the desired results, and such adjustments may cause the combustion air to exceed the ejection air at certain times, while at other times the ejection air may be the greater. No satisfactory mechanism has been available heretofore for controlling the direction of the flow and regulating the quantities of air supplied under the different operating conditions.

It is accordingly one object of the invention to provide a reversing apparatus for furnaces which will make it possible to adjust independently the air quantities supplied for combustion purposes and for ejection purposes.

It is a further object of the invention to provide a reversing apparatus for furnaces so constructed and arranged that the combustion air may be supplied at a rate either greater or less than the ejection air, as operating conditions may require.

It is a further object of the invention to provide a comparatively simple, inexpensive and foolproof mechanism for controlling the flow of air and gases in furnaces of the reversing type.

With these and other objects in view, as will be apparent to those skilled in the art, the invention resides in the combination of parts set forth in the specification and covered by the claims appended hereto.

Referring to the drawings illustrating one embodiment of the invention and in which like reference numerals indicate like parts.

Fig. 1 is a front elevation of a reversing apparatus;

Fig. 2 is a. side elevation of the reversing apparatus, with certain parts shown in section on the line 2-2 of Fig. 1;

Fig. 3 is an enlarged view in section on the line 3-3 of Fig. 2;

Fig. 4 is a View similar to Fig. 2, showing the parts positioned for a reversal of the flow;

Fig. 5 is an elevation of a modified form of reversing apparatus;

Fig. 6 is a view taken on the line 6-6 of Fig. 5;

Fig. 7 is a section on the line 'l'! of Fig. 5; and

Fig. 8 is a section on the line 88 of Fig. 5.

As illustrated particularly in Fig. 2, there is. provided a vertical passage l which connects with a reversible furnace (not shown), this passage being arranged for the introduction of combustion air to the furnace and the escape of gaseous products of combustion therefrom alternately, in accordance with a well-known practice. There may be several of these passages connected to the same furnace and arranged in two groups, one group serving to admit the air while the other group serves to Withdraw the gases and vice versa. A sleeve ll forms an upwardly contracting extension of each passage in, and this sleeve is surrounded by a casing I2 to the top of Which there is connected the lower end of a vertical stack l4 axially aligned with the sleeve II. This stack is provided with a pivotally mounted valve or damper I having an operating arm IS. The casing I2 is provided with a lateral opening I8 in its lower portion, and a vertically slidable gate l9 controls the area. of this opening. A horizontal duct communicates with the several openings I8 in a group of casings l2, and air is supplied to this duct by means of a suitable fan 2| (Fig. 1).

The parts as so far described are of well-known construction. It will be understood that with the damper 15 open as shown in Fig. 2 air will flow upwardly from the casing l2 into the stack l4, and the ejector action of the air flow will create a suction in the sleeve II and cause gaseous prodnets of combustion to be withdrawn from the furnace through the passage l0 and discharged from the stack. If now the damper I5 is closed as shown in Fig. 4 air will flow from the casing l2 into the upper end of the sleeve II and thence downwardly through the passage ID to the furnace to support combustion therein. Whether the damper I5 is open ,or closed, the rate of air flow may be controlled'by adjustment of the gate l9 Applicant has found that for the best results it is usually necessary to adjust the gate l9 to one position when the air is used for combustion, and to a different position when the air is used for ejection. Moreover it is often difiicult to ascertain in advance of actual installation and trial which of these conditions will require the greater gate opening. These difficulties are overcome by the apparatus disclosed herein.

In order to control the position of the air gates, there is mounted on the air duct 29 a series of brackets 23, one in front of each stack H5. Each of these brackets serves as a pivotal support for an actuating device or member 24 shaped as an inverted T, with an upwardly extending arm 25 and two opposite laterally extending arms 26 and 21. Those arms are all shown with forked ends. Means is provided to move each of the members 25 between two different positions, and for this purpose there is shown a horizontal bar 29 which is pivotally connected to the forked upper ends of the arms 25. This bar is connected at one end by a link 50 to a crank 3| which can be rotated through approximately |8|l degrees by means of worm gear 33 driven by a worm 3 3 and a hand crank The worm and gear are shown mounted in a. casing 8'. provided with stops 38 to limit the movement of the crank 3 i. It will be apparent that by turning the hand crank 55, it will be possible to move each of the actuating members 25 between two predetermined positions. It will be noted that with the members 25 positioned as shown in Fig. l, the ends of the arms 21 are lower than the ends of the arms 26, whereas the contrary will be true when the crank 3| is turned to its other position.

In the preferred construction illustrated, means is provided to form two separate independently adjustable lost-motion connections between each air gate i9 and the respective arms 26 and 21 of the corresponding actuating device 24. As shown in Fig. 2, an operating rod 49 extends upwardly from the gate l9, the upper end of this rod being connected by a link 4| to the rear end of a horizontal arm 42. The arm 42 is secured at its forward end to a horizontal shaft 44 which is rotatably supported in bearings 45 on the top of the air duct 25. A forwardly projecting arm 46 is secured to each end of the shaft 44, and each arm 46 is connected by a link 48 to the upper end of a vertical rod 49. The rods 59 are vertically slidable in guides 50 secured to the front of the air duct 29, and the lower ends of the rods are screw-threaded to receive internallythreaded sleeves or nuts 5| which are positioned directly beneath the forked ends of the arms 26 and 27. It will be understood that the rods pass through these forked ends without engaging the same.

In order to facilitate adjustment of the sleeves 5|, each sleeve is slidably secured by means of a key 53 (Fig. 3) to the surrounding hub of a hand-wheel 54. Each hand-wheel is rotatably supported in a bracket 55 mounted on the air duct 29. By turning the hand-wheel it is possible to rotate the sleeve on its rod and thus adjust the position of the sleeve axially of the rod.

The air gate i9 is biased toward closed position, and if the gate itself is not heavy enough for this purpose a weight 55 can be attached to the arm 42. With this construction it will be apparent that gravity acting upon the gate I9 and the weight 56 will tend to lift the rods 49 until further movement is prevented by engagement of one of the sleeves 5| with the end of the arm 26 or 21 (whichever is in the lower position). Thus the adjustment of the sleeves 5| on the rods 49 will determine the positions of the air gate corresponding to the two positions of the actuating member 24.

It is desirable to actuate both the air gate l9 and the damper l5 from the same mechanism. For this purpose a horizontal lever 51 is fulcrumed intermediate its length on the shaft 44 (but not keyed thereto). The front end of this lever is connected to the arm 2'! by a vertical rod 58, and the rear end of the lever is connected to the operating arm l6 of the damper l5 by a vertical rod 59. The damper I5 is biased toward closed position by the weight of the arm I6 and the rod 59, and in order to ensure tight closure of the damper the rod 59 is preferably formed with a slot 69 at its connection with the lever 5'1. This slot allows a small amount of lost motion between these connected parts, so that the damper will close tightly by gravity in spite of any slight variation or inaccuracy in the movement of the lever. The lower ends of the rods 58 are connected to the arms 21 by means of pins 62 which can be readily removed in the event the operator wishes to close the dampers 5 independently of the gate operating mechanism.

The operation of this embodiment of the invention will now be apparent from the above disclosure. With the parts in the positions shown in Figs. 1 and 2, the dampers l5 will be fully open, and the arms 2! will serve as stops to limit upward movement of the corresponding sleeves 5| therebeneath under the influence of gravity on the air gates l9 and weights 56. By adjusting these sleeves through the medium of the associated handwheels 54, it is possible to vary the positions of the air gates. The fan 2| will supply air to the duct 25, and this air will flow through the openings l8 into the casings I2, and thence upwardly into the stacks I l. These upwardly flowing air currents will create a suction in each of the passages l0 and withdraw gaseous products of combustion therefrom, these gases being ejected with the air from the stacks. If now the hand crank 35 is rotated to turn the crank 3| through 180 degrees, the rod 29 will be moved to the left in Fig. 1, lowering the arms 26 and raising the arms 27. This will raise the rods 58 and close the dampers 5 as shown in Fig. 4. At the same time the arms 26 will serve as stops to limit upward movement of the corresponding sleeves 5| therebeneath, and by adjusting these sleeves the positions of the air gates can be varied. Since the dampers I5 are now closed, the air which enters the casings l2 cannot flow upwardly through the stacks l4, but is compelled to fiow downwardly through the sleeves H and passages ID, this air being used to support combustion in a well-known manner. It will now be clear that by means of the hand-wheels 54 and sleeves 5| it is possible to adjust the positions of the air gates l9 when supplying ejection air entirely independently of their positions when supplying combustion air. While the air gate is shown fully open in Fig. 2 for ejection air and partially closed in Fig. 4 for combustion air, it is a simple matter to provide a greater gate opening for combustion air than for ejection air if operating conditions render this desirable.

In Figs. 5 to 8 there is shown a modified form of the invention comprising two passages 65. These passages may connect with a reversible furnace (not shown), the arrangement being such that while one passage supplies air for combustion the other passage serves for the escape of the gaseous products of combustion and vice versa, in a well-known manner. Above each passage 65 there is provided a sleeve 68 forming an upwardly contracting extension thereof, each sleeve being surrounded by a casing 61 to the top of which there is connected the bottom of a vertical stack 99. Each stack is provided with a valve or damper I8 having an operating arm II. Each casing 81 is provided with a lateral opening I3 in its lower portion, and a vertically slidable gate 14 controls the area of this opening. A horizontal duct I5 communicates with both openings I3, and air is supplied to this duct by means of a suitable fan I8.

For convenience in installation and operation, the control apparatus for the dampers and air gates is mounted for the most part on an upright frame or panel I8 located equidistant from the two stacks. Since the mechanism associated with one stack is the same as that associated with the other stack (except that they are of opposite hand), only one of these mechanisms will be described. This mechanism comprises an actuating device or member I9 pivotally supported on the frame I8 and shaped as an inverted T, with an upwardly extending arm 8| and two opposite laterallyextending arms 92 and 83. The upper end of the arm 8| is connected by a link to a crank 88 pivotally mounted on the frame I8 and operable through approximately 180 degrees by means of a hand-crank 81. Stops 88 limit the movements of the crank 86 and the crank is preferably movable slightly beyond dead center in each direction to form a self-locking toggle. Each lateral arm 82 and 83 is connected by a link 98 to the lower end of a vertical rod 9I. Each rod 9| is screw-threaded near its upper end to receive an internally threaded sleeve or nut 92, which is slidably secured by means of a key 94 (Fig. 8) to the surrounding hub of a handwheel 95. Each hand-wheel is rotatably supported in a bracket 98 mounted on the frame I8. By means of the hand-crank 81 one sleeve 92 can be raised while the other is lowered, and vice versa. Moreover, each sleeve can be adjusted in height independently of the other by means of its respective hand-wheel 95.

A horizontal shaft 98 is rotatably supported on the frame I8, and this shaft carries two parallel horizontally projecting arms 99, the ends of these arms being forked to straddle the upper portions of the rods 9|. With this construction, one of these arms 99 will contact with that one of the sleeves 92 which happens to be raised at the time, and this sleeve will serve as a stop to limit downward movement of the arm. On the end of the shaft 98 there is mounted an arm I88 which is connected by a horizontal rod I82 to an arm I83. This arm I83 is mounted on one end of a horizontal shaft I84 which is rotatably supported in brackets I85 carried by the air duct I5. On the other end of the shaft I84 is an arm I01 which is connected by a vertical rod I88 to the air gate I4. This gate is heavy enough to impart a turning movement to the shaft 98 and maintain contact between the raised sleeve 92 and the arm 99 associated therewith. In other words, the air gate is biased by gravity toward its closed position.

The member I9 also serves to actuate the damper I8, and for this purpose the upright arm 8| is connected by a link III] to a bell crank HI, and the latter is connected by a horizontal rod I I2 to an arm I I4 secured to one end of a horizontal shaft II5 rotatably supported in the brackets I05. On the other end of this shaft I I5 is an arm I I6 which is connected by a vertical rod I H to the arm II of the damper 18.

The operation of this embodiment of the invention will now be apparent from the above disclosure. With the parts positioned as shown in Fig. 5 the air supplied to the casing 87 at the right will be used for ejection of the gases from the corresponding passage I55, since 'the corresponding damper I8 is open. At the same time the air supplied to the casing 81 at the left will be compelled by the closed damper 18 to flow downwardly through the corresponding passage 65 and be used to support combustion of fuel in the furnace. The positions of the air gates 14, which control the rate of air flow to each casing, can be readily adjusted by turning the hand-wheels 95 associated with the proper sleeves 92. When it is desired to reverse the furnace it is merely necessary to turn the hand-cranks 81 approximately one-half a revolution until further movement is prevented by the stops 88, thus swinging the members I9 in a clockwise direction about their pivots. This will close the right-hand damper I8 and open the left-hand damper, at the same time raising the left-hand sleeve 92 of each pair into contact with the arm 99 thereabove. This will move the right-hand air gate 14 into the position required for supplying combustion air, and the left-hand air gate into the position required for supplying ejection air. Either of these gates can be readily adjusted by turning the proper handwheel 95.

It will now be clear that with either of the two constructions illustrated it is a simple matter to adjust the combustion air independently of the ejection air. Moreover, the combustion air may be readily supplied at a rate either greater or less than the ejection air, as may be found desirable. Both constructions are comparatively simple and inexpensive to manufacture, and foolproof and reliable in operation.

Having thus described my invention, what I claim as new and desire to secure by Letters Patent is:

1. A'reversing apparatus for a furnace comprising an air control device biased to move in. one direction, a pair of stops each movable between an operative position and an inoperative position, and means connected to the stops and serving to move one stop to its inoperative position when the other stop is moved to its operative position and vice versa, each stop when in its operative position serving to limit the movement of the air control device under its bias.

2. A reversing apparatus for a furnace comprising an air control device biased to move in one direction, an actuating device movable between two different positions, a pair of stops arranged to be moved by the actuating device alternately into operative and inoperative positions, and means providing lost motion connections between the air control device and the stops, each stop when in its operative position serving to limit the movement of the air control device under its bias.

3. A reversing apparatus for a furnace comprising an air control device biased to move in one direction, an actuating device movable between two different positions, and two separate lostmotion connections between the actuating device and the air control device to limit movement of the air control device under its bias, one of said connections being effective when the actuating device is in one position and the other of said connections being effective when the actuating device is in the other position.

4. A reversing apparatus for a furnace comprising an air control device biased to move in one direction, an actuating device movable between two different positions, and two separate lost-motion connections between the actuating device and the air control device to limit movement of the air control device under its bias, one of said connections being effective when the actuating device is in one position, and the other of said connections being effective when the actuating device is in the other position, and means providing a separate and independent adjustment of the lost-motion in each of said connections.

5. A reversing apparatus for a furnace comprising an air control device biased to move in one direction, an actuating device movable between two dilferent positions, a pair of stops arranged to be moved by the actuating device alternately into operative and inoperative positions, and a pair of members connected to the air control device and each arranged to engage one of the stops when it is in operative position to limit the movement of the air control device under its bias, each of said members being adjustable independently of the other member relative to the air control device.

6. A reversing apparatus for a furnace comprising an air control device biased to move in one direction, an actuating device movable between two different positions, a pair of stops arranged to be moved by the actuating device alternately into operative and inoperative positions, and a pair of members connected to the air control device and each arranged to engage one of the stops when it is in operative position to limit the movement of the air control device under its bias, each of said stops being adjustable independently of the other stop relative to the actuating device.

7. A reversing apparatus for a furnace comprising an air control device biased to move in one direction, a pair of stops each movable between an operative position and an inoperative position, and a pivotally mounted actuating member connected to the stops and serving to move one stop to its inoperativeposition when the other stop is moved to its operative position and vice versa, each stop when in its operative position serving to limit the movement of the air control device under its bias.

8. A reversing mechanism for a furnace comprising a passage arranged for the introduction of combustion air and the escape of gaseous products of combustion alternately, a casing connected with the passage, means to supply air to the casing, a device to control the rate of air supply, a valve movable between two positions, the valve serving when in one position to direct the air into the passage for combustion purposes and when in the other position to allow the air to effect withdrawal of the said gaseous products from the passage, an actuating device movable between two positions, means operatively connecting the actuating device to the valve, and means operatively connecting the actuating device to the air control device, the last mentioned means being adjustable to vary independently the position of the air control device corresponding to each position of the actuating device.

9. A reversing mechanism for a furnace comprising a passage arranged for the introduction of combustion air and the escape of gaseous products of combustion alternately, a casing connected with the passage, means to supply air to the casing, a device to control the rate of air supply and biased to move in one direction, a valve movable between two positions, the valve serving when in one position to direct the air into the passage for combustion purposes and when in the other position to allow the air to effect withdrawal of the said gaseous products from the passage, a pair of stops each movable between an operative position and an inoperative position, and means connected to the stops and serving to move one stop to its inoperative position and the other stop to its operative position and vice versa, each stop when in its operative position serving to limit the movement of the air control device under its bias.

10. A reversing mechanism for a furnace comprising a passage arranged for the introduction of combustion air and the escape of gaseous products of combustion alternately, a casing connected with the passage, means to supply air to the casing, a device to control the rate of air supply and biased to move in one direction, a valve movable between two positions, the valve serving when in one position to direct the air into the passage for combustion purposes and when in the other position to allow the air to effect withdrawal of the said gaseous products from the passage, a pair of stops each movable between an operative position and an inoperative position, an actuating device connected to the stops and serving to move one stop to its inoperative position and the other stop to its operative position and vice versa, each stop when in its operative position serving to limit the movement of the air control device under its bias, and means operatively connecting the actuating device to the valve.

11. A reversing apparatus for a furnace comprising an air control device, an actuating device movable between two positions, and means connecting the actuating device to the air control device, said means including two independently adjustable elements, one of said elements determining the position of the air control device corresponding to one position of the actuating device, and the other of said elements determining the position of the air control device corresponding to the other position of the actuating device.

GUSTAV A. MERKT. 

